Issue with squaring XY cross bars

I assembled the middle section that the XY cross brass pass through with no issues. I snugged everything down just to the point where there was no wobble in the bearing and the C tension bolts to where the nut just touches the plastic. When I put it on the machine and move it around the x axis bar measures the same on both sides. However when I put in the Z gantry it pushes the two ends out by 3/8th constantly. I can move it back to be the same measurement but not sure if the end stops will be able to square it being this far out. I have disassembled it and put it back together and same issue. I have tried to listen and tighten the C and B tension bolts and nothing seems to work. I’m including a few pics.

As a side note this is a burley build that I printed 2 years ago and just never got to assembling. All hardware was purchased directly from here. Working area is 36 x 24 y with mid supports for the x axis.

First set of pics is without the x gantry in then with it in.

Now the left hand side of the x axis with the gantry in and the right side still reading the same as prior.

As you can see putting in the z gantry it pushes the left side 3/8 out from the right.

Any help would be greatly appreciated.